The state of the ocean climate
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Southern Oscillation Index (SOI)

The SOI index is the normalized difference in pressure between Darwin, Australia and Tahiti. It is associated with El Niño and La Niña phases of ENSO.

In the shorter series case, monthly averages are shown by the plus signs and 3-month running mean filtered index values are shown by the shaded regions. In the longer series case, 3-month averages are shown by the plus signs and 12-month running mean filtered index values are shown by the shaded regions. The monthly standard deviation of the index over the period 1948-2005 is indicated on each plot. get series (netcdf 12kB) »

Data source and calculation

The index is calculated by NOAA/CPC (last update 15-OCT-2024). view details of calculation »

The standard deviation of the index over the period 1948-2005 is indicated on the plot. get series (netcdf 12kB) »

 

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